2018 Hyundai Sonata
Common Problems
Ranked from 169 federal NHTSA complaints. Every problem links to the complaint IDs behind it.
17 Common Problems
Ordered by how often owners reported each one to NHTSA. The bar shows how common a problem is relative to the most-reported on this vehicle. Expand any problem to see the federal complaint IDs.
- 1
Engine Failure and Loss of Power
62complaintsHigh severityEngineThe engine fails and loses power, often resulting in the vehicle becoming undrivable.
$4,000–$8,000est. engine replacement · 12–20 hrs laborGet local quotes - 2
Engine Misfires and Knocking Noise
45complaintsHigh severityEngineThe engine misfires and produces knocking or pinging sounds during operation.
$200–$900est. ignition service (coils/plugs) · 1–4 hrs laborGet local quotes - 3
Excessive Oil Consumption
30complaintsHigh severityFuel systemThe engine consumes an abnormally high amount of oil, requiring frequent refills.
$400–$4,500est. oil-consumption repair (rings/pcv) · 3–14 hrs laborGet local quotes - 4
High Oil Consumption
29complaintsHigh severityEngineThe engine consumes an excessive amount of oil, requiring frequent refills.
$400–$4,500est. oil-consumption repair (rings/pcv) · 3–14 hrs laborGet local quotes - 5
Engine Oil Light On and Low Oil Levels
26complaintsMedium severityFuel systemThe engine oil light illuminates, and the oil level drops below normal, requiring frequent refills.
- 6
Headlight Malfunction Causing Poor Visibility
16complaintsHigh severityElectricalLow beam headlights do not project far enough, leading to poor visibility at night.
$100–$900est. lighting assembly repair · 0.5–2 hrs laborGet local quotes - 7
Check Engine Light On Without Clear Diagnosis
11complaintsMedium severityElectricalThe check engine light comes on without clear indication of the issue, requiring multiple tests and repairs.
$100–$250est. professional diagnosis · 1–2 hrs laborGet local quotes - 8
Engine oil consumption leading to frequent oil changes
8complaintsMedium severityEngineThe engine consumes oil rapidly, requiring frequent refills.
$400–$4,500est. oil-consumption repair (rings/pcv) · 3–14 hrs laborGet local quotes - 9
Engine Stall at Low Speeds Due to Knock Sensor Failure
6complaintsMedium severityEngineThe engine stalls or hesitates at low speeds, causing difficulty in accelerating.
$150–$1,200est. stalling / shutdown diagnosis + repair · 1–5 hrs laborGet local quotes - 10
Unexplained Smoke and Fire Risk
6complaintsSafety riskEngineThe engine emits smoke and there is a risk of fire due to oil pan issues.
- 11
Spark Plug and Coil Issues
5complaintsMedium severityEngineSpark plugs and coils frequently fail, requiring frequent replacements.
$200–$900est. ignition service (coils/plugs) · 1–4 hrs laborGet local quotes - 12
Engine Malfunction After Software Update
4complaintsHigh severityEngineAfter software update, the engine malfunctions, causing the car to enter limp mode or fail to start.
- 13
Headlight Shadow Distortion
4complaintsLow severityOtherHeadlights show distinct shadows with notches or lines, affecting night vision.
$100–$900est. lighting assembly repair · 0.5–2 hrs laborGet local quotes - 14
Unintended Acceleration
4complaintsHigh severityOtherThe vehicle accelerates unexpectedly, even when the driver does not apply the gas pedal.
- 15
Paint peeling off the vehicle body
3complaintsLow severityOtherThe white paint on the vehicle body begins to peel off, affecting the appearance and potentially the structural integrity.
- 16
Faulty Engine Oil Pan
2complaintsHigh severityEngineThere is a hairline crack in the engine oil pan leading to oil leakage and potential engine failure.
$200–$1,600est. oil-leak repair · 1–8 hrs laborGet local quotes - 17
Steering Lock-up
2complaintsHigh severitySteeringThe steering wheel locks up, making it impossible to steer the vehicle, posing a severe safety risk.
$200–$1,500est. power-steering / eps repair · 1–6 hrs laborGet local quotes
Other years & sources
Data source: U.S. National Highway Traffic Safety Administration (NHTSA) owner complaints and recalls. Problems are clustered and ranked from the complaint record; occurrence counts reflect corroborating complaints, not total incidence. Vehicle image is illustrative. Repair-cost figures are typical U.S. independent-shop ranges (parts + labor) for the class of repair shown — actual quotes vary by region, engine, and diagnosis; always confirm with a local shop.